WO2019237216A1

WO2019237216A1 - Low-notch microdynamic pedicle screw having buffering function

Info

Publication number: WO2019237216A1
Application number: PCT/CN2018/000306
Authority: WO
Inventors: 何伟义
Original assignee: 何伟义
Priority date: 2018-06-13
Filing date: 2018-08-28
Publication date: 2019-12-19
Also published as: CN108720918A

Abstract

A low-notch microdynamic pedicle screw having a buffering function, comprising a screw plug (5), a connecting bar (4), a screw seat (3), a spring (2), and a ball-head screw (1). The upward end of the ball-head screw (1), i.e., the head, is spherical; a plane (12) is provided at the top end; an annular recess (11) is provided on the plane; the spring (2) is disposed in the recess (11). The pedicle screw has low notch, multiple axial directions, and a buffering function.

Description

Low-notch micro-dynamic pedicle screw with buffer function

Technical field

The application of the present invention relates to an artificial implant applied to treat lumbar intervertebral disc disease in orthopedic surgery, and specifically, it is suitable for use in orthopedic surgery, and is different from the traditional "rigid fixed fusion surgery". In the advanced discipline of "non-fixed fusion surgery", a new type of pedicle screw is being explored and developed.

Background technique

Lumbar disc herniation and lumbar spinal canal stenosis are common diseases in modern people's lives. In traditional surgical treatment, it is often used to remove the protruding intervertebral disc and enlarge the narrow nerve root canal while using the spine "rigid fixed fusion surgery" for treatment. The pedicle screws that are used with it, including uniaxial nails and universal screws, are called fixed nails. With the continuous deep research of traditional disciplines, it has been found that if the pedicle is implanted after the operation is completed, The vertebral body of the nail can still oscillate at a certain angle relative to the connecting rod, which can stimulate and promote the healing of the diseased part; this type of concept that is gradually being accepted by the academic community is "non-fixed fusion surgery". Pedicle screws are called "dynamic nails".

Due to the concept of "dynamic nails", it is still under exploration and in continuous practice, many proposals have been made: for example, the patent No. CN201085680Y, the inner suspension type named "pin-type spinal nail rod fixation nail"; For another example, the patent number is 201510173832.8, and the name is "Posular and acetabular rail chain reduction and fixation dynamic pedicle screw system", etc., or it is unable to achieve the "multi-axial" function, which increases the difficulty of surgery; Low; for example, the patent No. 201620153647.2, the "a kind of micro-dynamic pedicle screw", although the above two shortcomings are avoided, the "notch" is still too high.

The so-called "notch" is the height of the pedicle screw after it is implanted in the vertebral body of the human, and the height of the vertebral body is exposed. In a simple description, it is the height of the nail seat. In summary, clinically, in addition to the basic characteristics of "dynamic nails" that have a minimum of "the ability to swing after implantation is complete", they should also have "multi-axial" functions that facilitate clinical operations. The structure is simple and practical, and has the function of "buffering" that can reduce the impact force on the vertebral body, and requires as low as possible notches. So many factors are clinical scholars, and the ideal "dynamic nail" The requirements put forward are also technical problems that need to be solved urgently in the clinical practice of orthopedics.

Summary of the Invention

The present application discloses a technical solution capable of effectively solving the above several technical problems at the same time, which is to modify the “universal nail” in the “fixing nail” used in the traditional “rigid fixed fusion surgery” and cancel it. The pressure block was added, the spring was added, and the structure of one of the parts, that is, the head of the ball stud, was improved to meet the basic function of "micro dynamics", and also to meet the "low notch", "Multi-axial", simple and practical, can reduce the impact of the impact of the clinical technical effects.

The technical solutions adopted by the present invention to solve its technical problems are as follows:

First, the top of the spherical head of the ball stud in the traditional "universal nail" is processed into a plane. In this plane, in addition to the original blind hole used with the screwdriver, A circular groove is machined.

Further, the spring is a column-shaped compressible type, and both ends are processed into a flat bottom shape that is convenient for vertical standing, so as to be conveniently placed in an annular groove on the ball stud.

Still further, the spring is placed in the annular groove, and the bottom end surface of the spring is permanently and fixedly connected to the bottom surface of the annular groove, and under no load state, The natural height of the spring should protrude from the plane of the top end of the ball stud.

Furthermore, the width of the annular groove should be slightly larger than the wire diameter of the spring, so that the spring can freely expand and contract with a slight swing in the annular groove.

Furthermore, in addition to the internal thread, U-shaped through groove and the like common to the conventional "universal nail", the bottom of the U-shaped through groove is used to replace the cancelled block. To support the connecting rod, and the bottom of the U-shaped through groove should be higher than the plane of the top end of the ball stud after the assembly is completed, but it should be lower than that of the spring in the natural state after the assembly is completed. Top surface.

Still further, a pair of kinematic pairs formed by the spherical head of the ball stud and the inner spherical surface in the hollow cavity of the nail seat are all coated with abrasion resistance, or Heat treatment process for anti-wear treatment.

Furthermore, a process hole is provided on the side of the bottom of the annular groove of the ball stud. Through this process hole, the bottom end surface of the spring can be fixed by physical means such as welding and pins. At the bottom of the annular groove to prevent the spring from slipping out of the annular groove.

BRIEF DESCRIPTION OF THE DRAWINGS

The following are descriptions of the drawings and specific features:

FIG. 1 is a two-dimensional view and a partially enlarged view of the application of the present invention;

Figure 2 is an effect diagram of the application of the present invention;

Figure 3 is an explosion effect diagram of the application of the present invention;

FIG. 4 is a two-dimensional comparison view of the application of the present invention before and after the connection rod is placed;

Figure 5 is a two-dimensional schematic diagram of the working principle of the application of the present invention;

6 is a schematic diagram of a process hole for fixing a spring in a groove in an embodiment of the present application;

among them:

Ball stud 1; spring 2; nail seat 3; connecting rod 4; screw plug 5;

Annular groove 11 on ball stud; plane 12 on ball stud; blind hole 13 on ball stud; spherical surface 14 on ball stud;

Technological holes 15 on ball studs; swing ball center O of ball studs;

The top end surface 21 of the spring 2; the bottom end surface 22 of the spring 2;

The bottom 31 of the U-shaped through groove on the nail base; the U-shaped through groove 32 on the nail base; the internal thread 33 on the nail base; the inner spherical surface 34 on the nail base

detailed description

Hereinafter, the application of the present invention will be further described with reference to the accompanying drawings:

From the two-dimensional diagram of the application of the present invention shown in FIG. 1, it may be seen that: the pressing block in the conventional fixing nail is eliminated, and the spring 2 is added; and the screw plug 5 and the connecting rod 4 in the conventional fixing nail are used. In addition, because the bottom 31 of the U-shaped through groove of the nail base 3 is moved downward, the height of the entire nail base 3 is reduced by about 5 mm compared with the notch of the conventional fixed nail.

From the partially enlarged view of FIG. 1, it can be seen that the technical features shown in the application of the present invention: the downward end of the ball stud 1, that is, the tail, is the same as the traditional fixing nail, and is a section of screw for implantation into the human body. The vertebral body is used for fixation; the top of the spherical head of the ball stud 1 is processed into a plane 12, and after multiple tests and comparisons, the plane is set in this embodiment of the present application. 12 is located 1 mm above the ball center O of the head of the ball stud 1 so that on this plane 12 there is a sufficient plane allocated to the blind hole 13 for the screwdriver and the annular groove 11 for the spring 2 At the same time, it can also ensure that the ball stud 1 acts about its center of mass O and limit when it swings.

FIG. 2 is an effect diagram of the application of the present invention. In combination with FIG. 1, it can be clearly seen that, when the connecting rod 4 is not yet inserted, the top surface 21 of the spring 2 is a ball head protruding from the ball head. The plane 12 on the nail is higher than the bottom 31 of the U-shaped through groove. In this embodiment of the present application, after testing and observation of the template, it is considered that: h = 0.4 to 0.6 mm, and H = 1.2 to 1.5mm is appropriate;

In order to more clearly express the features shown in the application of the present invention, an attempt is made in the exploded view shown in FIG. 3: the annular groove 11 and the blind hole 13 on the ball stud are located on the same side of the ball stud. On the plane 12; both the bottom end surface 22 and the top end surface 21 of the spring 2 are processed into a plane that is convenient for erecting; the bottom of the annular groove 11 has a process hole 15.

As shown in the left figure of FIG. 4, when the connecting rod 4 is not inserted, the vertical distances between the bottom 31 of the U-shaped through groove and the top surface 21 of the spring 2 and the plane 12 on the ball stud are H and h; After the connecting rod 4 is implanted and the screw plug 5 is locked, the connecting rod 4 is directly supported by the bottom 31 of the U-shaped through groove because the pressing block is cancelled. In this state, the connecting rod 4 and the ball stud The gap between the upper planes 12 is K, as shown in the right figure of FIG. 4, that is, K = h;

The working principle of the application of the present invention, that is, the technical effects that can be produced by its features, can be clearly seen from FIG. 5 that when a human vertebral body is subjected to an external force, this external force can be basically decomposed into a ball stud perpendicular to the ball stud. The radial component force Fx of the axis of 1 and the axial component force Fy parallel to the axis of the ball stud 1; as shown in the left figure of FIG. 5: When Fy acts, the ball stud 1 moves up as a whole, so that the ball The spherical surface 14 on the stud is temporarily separated from the inner spherical surface 34 on the nail seat; the spring 2 is compressed again, and the gap between the connecting rod 4 and the plane 12 on the ball stud is compressed from K to S, which is exactly this The compression indicates that the spring 2 has a buffering effect, that is, it has absorbed the axial component force Fy and converted it into potential energy to store it.

Similarly, as shown on the right side of FIG. 5, when Fx acts, the ball stud 1 will swing around its center of mass O, and at the same time, it will cause the spring 2 to deform and bend; especially when the external force F shows a sudden impact force This buffering effect is more obvious, and when F disappears or decreases, the spring 2 will inevitably release the stored potential energy and return to the natural state shown in the right side of FIG. 4-this is the application of the present invention Has a buffer function.

As shown in the left figure of FIG. 5, the so-called “notch” can be roughly regarded as the height Q of the nail seat 3. The pedicle screws currently in use, whether they are traditional fixing screws or just started The notch of popular dynamic nails is generally 17 ～ 19mm. Because the specific size of the screw plug 5 and the connecting rod 4 has been determined by its function, it has basically become a fixed value and can no longer be compressed. The only possible way is An improvement is made on the head of the ball stud 1; the technical solution adopted in the application of the present invention is: the traditional pressing block is eliminated, and the connecting rod 4 is supported by the bottom 31 of the U-shaped through groove; the plane 12 on the ball stud 1 It is reduced to only about 1mm above its center of mass, which saves considerable space. As in the embodiment of the present application, the height of .j is only less than 3mm, that is, in the embodiment of the present application, The notch height Q can be controlled below 14 mm. This is the low notch function possessed by the present application.

As shown in the partial enlarged view of FIG. 1, in the clinical operation, even if the ball stud 1 implanted in the vertebra of the patient has a positional deviation from the adjacent implanted pedicle screw, (clinical The jargon is called: the nails are misaligned; the adjacent U-shaped grooves 32 of the connecting rods 4 are not overlapped with each other), the operator may be able to make a certain degree of correction by swinging the nail base 3 ----- This is the "multi-axial" function of the present application.

After a period of testing, it has been proved that the "buffer function" can effectively reduce the medical accidents of "nail loosening and breaking," but the space left for the spring 3 is very limited. Some practitioners think of ways on the spring, even because there is too little space While trying to cancel the spring; the technical solution shown in the application of the present invention can solve this problem very cleverly: it is to lower the plane 12 on the ball stud, which not only reduces the notch, but also the blind hole on the ball stud 13 and the ring-shaped groove 11 leave an allocatable space; and the ring-shaped groove 11 sunk in the plane 12 of the ball stud, it is possible to place the spring 3, and thus the spring 3 has space to buffer And the role of swing ------- This is the simplest and most practical part of this utility with the most novelty and operability.

In the development and sample test of the application of the present invention, the center diameter of the annular groove 11 selected in this embodiment is 5 mm, the groove width is 1 mm, and the groove depth is 2.2 to 2.5 mm; and the wire diameter of the spring 2 is 0.7 to 0.8mm, line spacing is about 1.5mm, and the height of the spring 2 is about 3.5mm. Under this parameter, the pedicle screws shown in the present application have achieved satisfactory clinical results.

Since the spherical surface 14 on the ball stud and the inner spherical surface 34 on the nail seat form a set of motion pairs, the contact surface of the set of motion pairs, coupled with a coating or surface treatment that can reduce wear, can reduce The mutual wear that occurs.

It is worth noting that, as mentioned earlier, the concept of "non-fixed fusion surgery" is still under continuous exploration and practice, and "micro-dynamics to promote fixed fusion" and "non-fused fixation" are equally different branches of this concept. The main difference is that the former uses small swings to stimulate wound healing; the latter uses larger swings to promote a positive interaction between the vertebral body after surgery and the adjacent vertebral body, thereby avoiding lesions The extension of the part; as for the specific swing angle, it is still in the process of continuous discussion, and the technical solution shown in the application of the present invention can also produce technical effects in accordance with the above two directions of exploration; as shown in the right figure of FIG. 4 As shown, as long as the gap K between the bottom 31 of the U-shaped through groove and the plane 12 on the ball stud and the parameters of the corresponding spring 2 are adjusted, different swing angles can be achieved.

In the embodiment of the present application, when K = 0.3 to 0.5 mm, the swing angle is about 2 to 4 degrees; and when K = 1 to 1.5 mm, the swing angle can reach 8 to 12 degrees; Regardless of the development of the concept of "non-fixed fusion surgery", whether it is in the direction of "micro-dynamics to promote fixed fusion" or "non-fused fixation", and regardless of the required quantification result of the swing angle, the present application only needs to adjust some Parameters to meet their clinical needs. ----- This is also the forward-looking part of the application of the present invention.

FIG. 6 shows one of the methods of fixing the spring 2 to the bottom surface of the annular groove 11, namely, drilling a craft hole on the side, and making the bottom end surface 22 of the spring 2 permanent by welding or pins, etc. It is fixed on the bottom surface of the annular groove 11 to prevent it from falling off.

The above embodiment is a preferred implementation of the application of the present invention, and other principles and basic structures that are the same or similar to this embodiment are all within the protection scope of the present application.

Claims

A low-notch micro-dynamic pedicle screw with a buffer function includes a screw plug, a connecting rod, a nail seat, a spring, and a ball stud, characterized in that the upward end of the ball stud is the head, It is spherical, and a flat surface is machined on the top end. On this plane, a ring-shaped groove is provided, and the spring is arranged in the groove.
The pedicle screw according to claim 1, wherein the spring is a column-shaped compressible type, and both ends are processed into a flat bottom shape that is convenient for vertical standing.
The pedicle screw according to claim 2, wherein after the spring is disposed in the annular groove, the bottom end surface of the spring should be permanently fixed to the bottom of the groove, and the The natural height should protrude from the plane of the top of the ball stud.
The pedicle screw according to claim 1, wherein the width of the groove of the annular groove on the ball stud should be slightly larger than the wire diameter of the spring, so that the spring can be made. In the groove, free expansion and contraction and slight swing are performed.
The pedicle screw according to claim 1, characterized in that: the center of the plane of the top end of the ball stud is provided with a blind hole used in conjunction with a screwdriver; the downward end of the ball stud , That is, the tail, is a section of screw with a thread on the outer surface.
The pedicle screw according to claim 1, characterized in that: the nail seat is a hollow cylinder, the bottom of the hollow cavity is an inner spherical surface, and cooperates with the head of the ball stud, The tail portion of the ball stud penetrates from below the nail seat.
The pedicle screw according to claim 6, characterized in that: an internal thread is provided above the nail seat, cooperates with the screw plug, and is perpendicular to the axis of the nail seat A U-shaped through groove is opened, and the bottom of the U-shaped through groove is used for supporting the connecting rod.
The pedicle screw according to claim 7, characterized in that the bottom of the U-shaped through groove on the nail seat should be higher than the plane of the top end of the ball stud after the assembly is completed, but should be low The top surface of the spring in its natural state.
The pedicle screw according to claim 1, characterized in that: a pair of movement pairs formed by a spherical head of the ball stud and an inner spherical surface at the bottom of the hollow cavity of the nail seat. In the middle, all are used for anti-wear surface treatment.
The pedicle screw according to claim 1, characterized in that: on the ball stud, a side of the bottom of the annular groove is provided with a craft hole for connecting the spring The bottom end surface is fixed to the bottom of the annular groove by means of welding, pins, and the like.